1. Field
The present disclosure relates to a fuel cell stack.
2. Description of the Related Art
For example, a solid polymer electrolyte fuel cell includes a membrane electrode assembly (MEA), in which an anode electrode is disposed on one side of an electrolyte membrane and a cathode electrode is disposed on the other side of the electrolyte membrane. The electrolyte membrane is made from a solid polymer ion-exchange membrane. The MEA and a pair of separators, sandwiching the MEA therebetween, constitute a power generation cell. Typically, a predetermined number of such power generation cells are stacked and used, for example, as a vehicle fuel cell stack, which is mounted in a fuel cell vehicle (fuel cell electric automobile or the like).
In a fuel cell, a fuel gas channel for supplying a fuel gas to the anode electrode and an oxidant gas channel for supplying an oxidant gas to the cathode electrode are formed on surfaces of the separators. A coolant channel, through which a coolant flows, is formed between adjacent separators so as to extend in the in-plane direction of the separators.
Some fuel cells have a so-called internal manifold structure, in which a fuel gas manifold, through which a fuel gas flows, an oxidant gas manifold, through which an oxidant gas flows, and a coolant manifold, through which a coolant flows, extend through the fuel cells in the stacking direction. The fuel gas manifold has a fuel gas inlet manifold and a fuel gas outlet manifold, the oxidant gas manifold has an oxidant gas inlet manifold and an oxidant gas outlet manifold, and the coolant manifold has a coolant inlet manifold and a coolant outlet manifold.
In the aforementioned fuel cell stack, a fluid manifold member is disposed on at least one of the end plates. The fluid manifold member is connected to the fuel gas manifold, the oxidant gas manifold, or the coolant manifold, and serves to supply or discharge a fluid (a fuel gas, an oxidant gas, or a coolant). A liquid supply pipe or a liquid discharge pipe is connected to the fluid manifold member. The fluid manifold member is typically made of a resin. Therefore, there is a problem in that, for example, if an external load is applied to the fuel cell stack, the fluid manifold member is likely to become damaged due to a stress generated in the fluid manifold member.
For example, Japanese Unexamined Patent Application Publication No. 2011-065869 discloses a fuel cell stack for solving the problem. The fuel cell stack has a pipe connection structure for connecting a fluid manifold to an external pipe. The pipe connection structure is disposed on at least one of end plates and includes a resin manifold member (fluid manifold member) connected to the fluid manifold and a pipe connection portion, which is formed on the resin manifold member and to which the external pipe is connected.
A breakable portion, which becomes broken first when a load is applied from the outside, is formed between the resin manifold member and the pipe connection portion so as to be located below an electric power output terminal, which protrudes from the end plate.
Thus, it is possible to cause the resin manifold member to be broken at a desired position without fail when a load is applied from the outside, and it is possible to reduce the probability that the electric power output terminal becomes covered with a liquid.